Motor fuel composition



United States Patent 3,403,014 MOTOR FUEL COMPOSITION Ronald W. Von Allmen, Hopewell Junction, and Stanley R. Newman, Fishkill, N.Y. (both Texaco Inc., P.O. Box 509, Beacon, N.Y. 12508) No Drawing. Filed Nov. 5, 1965, Ser. No. 506,575 5 Claims. (Cl. 4472) This invention relates to a volatile gasoline composition having improved anti-stalling and improved surface ignition properties. More particularly, the invention involves the discovery that quaternary ammonium borohydrides are effective anti-stalling anti-icing and surface ignition additives for gasoline.

The gasoline fuel composition of this invention comprises a substantial concentration of volatile components and from about 0.001 to 0.1 wt. percent of a quaternary ammonium borohydride of the general formula:

wherein R, R, R" and R represent hydrogen or a hydrocarbyl radical containing from 1 to 24 carbon atoms and the sum of the carbon atoms in R, R, R", and R' equals at least 18 carbon atoms.

When internal combustion engines are operated on a gasoline fuel having the desired volatility characteristics for cold weather driving, a stalling problem is encountered during the warm-up period particularly under cool, humid, atmospheric conditions. It has been generally recognized that the cause of repeated engine stalling in cool, humid weather is the formation of ice in the carburetor. Gasoline evaporating in a carburetor has sufficient refrigerating effect to condense and freeze moisture present in the air. Ice particles deposit on the metal surfaces of the carburetor and partially or completely block the air passage between the carburetor throat and the carburetor throttle valve with resulting stalling particularly when the engine is idling.

The quaternary ammonium borohydrides are particularly useful in highly volatile fuels having a Reid vapor pressure above about 9 which are prone to engine stalling due to ice formation under cool, humid conditions. The additives of this invention are especially useful in winter gasoline employed in northern portions of the country since such fuels have Reid vapor pressures between about 9 and 13.5 depending on the area in question.

Internal combustion, spark ignition engines frequently experience abnormal combustion when operated under high compression ratios. Such abnormal ignition may occur either before or after normal ignition and gives rise to conditions known as rumble, knock, engine roughness, missing or after-firing.

Abnormal ignition is believed to be caused by incandescent particles of combustion products deposited on the combustion chamber Walls. These incandescent particles ignite the fresh fuel-air mixture during the compression step and upset the normal ignition behavior of the engine. The quaternary ammonium borohydrides are effective for substantially reducing the level and incidence of surface ignition of a motor fuel composition.

The quaternary ammonium borohydrides of the present invention which provides significant improvements in anti- 3,403,014 Patented Sept. 24, 1968 icing anti-stalling and in surface ignition properties have the general formula:

in which R, R, R" and R represent hydrogen or a hydrocar-byl radical having from 1 to 24 carbon atoms and the sum of the carbon atoms in R, R, R" and R'" is at least 16. The preferred quaternary ammonium borohydrides are those in which R, R, R" and R' are aliphatic radicals having from 1 to 12 carbon atoms and the sum of the carbon atoms in R, R, R" and R is at least 24.

Examples of specific quaternary ammonium borohydrides of the invention include tricapryl methylammonium borohydride, tristearyl methyl ammonium borohydride, trilaurylmethyl ammonium borohydride, tricaprylstearylammonium borohydride, dimethyldistearylammonium borohydride, tricaprylethylammonium borohydride distearyl diethyl ammonium borohydride and dicapryl di butyl ammonium borohydride.

The quaternary ammonium borohydrides are effective additives in concentrations of 0.001 to 0.1 wt. percent of the gasoline. The preferred concentration falls in the range of 0.001 to 0.02 wt. percent. Concentrations in the order of 10 to 32 lbs. per 1000 barrels of gasoline, equivalent to concentrations of 0.0037 to 0.012 wt. percent have proven particularly effective fuels of excellent anti-stalling properties while higher concentrations in the range of 0.05 to 0.1 wt. percent are preferred for outstanding improvements in the surface ignition properties of gasoline.

The action of the quaternary ammonium borohydrides as anti-stalling, anti-icing additives Was evaluated in a carburetor icing demonstrator apparatus consisting of a vacuum pump equipped so that cool, moisture-saturated air from an ice tower is drawn through a simple glass tube gasoline carburetor. The gasoline sample is placed in a sample bottle and is drawn into the glass carburetor through a hypodermic needle of 20 gauge. Evaporation of the gasoline in the glass tube further cools the cold moist air with resulting ice formation on the throttle plate. The formation of ice on the throttle plate causes an engine to stall and has been found that this condition is equivalent to a pressure drop across the throttle plate of about 0.5 inch of mercury and the time to reach this pressure drop is recorded. A vacuum pump is adjusted to give above a vacuum of 1.8 inches of mercury and the test is run until a pressure of 2.3 inches of mercury has been reached or is run for 300 seconds. Since with most fuels this pressure drop is reached in 1 to 4 minutes, 300 seconds is the maximum time for a run. A recording of '300 seconds indicates no stall within the test period. Each fuel is run three times in succession and the average is reported. It the differences between the runs are great, the glass tube carburetor and the test throttle are washed with alcohol and the runs repeated. A leaded winter grade premium gasoline having a Reid vapor pressure of about 13 gives a stall in about 45 to seconds in this test. Additives which raise the stalling time to 200 seconds or more are effective anti-stalling, anti-icing additives.

The basic fuel employed to evaluate the effect of the quaternary ammonium borohydrides as anti-stalling, antiicing additives was a winter grade premium gasoline having an octane rate of about 101.4 containing 3 cc.s of

TEL per gallon. This winter grade gasoline, which had a 50 ASTM distillation point of 220 F. and a Reid vapor pressure of about 1-1.8 lbs. was ideally suited for testing the effect of quaternary ammonium borohydrides on stalling characteristics because of its high vapor pressure. The base fuel had an average stalling time of 45 seconds in the above described stalling test.

The effectiveness of quaternary ammonium borohydrides as anti-stalling, anti-icing gasoline additives is shown in the following table.

ACTION OF QUATERNARY AMMONIUM BOROHYDRIDES The surface ignition test was conducted in a cylindrical wedge single cylinder 11.3 combusiton ratio overhead valve engine equipped with a Champion No. 1 commercial spark plug and a Champion Ionization pick-up N0. ED- 16. The time was set at TDC (Top Dead Center): /2 degree. When a surface ignition flame front (abnormal flame front) occurs the instrumentation records a count, but does not count normal spark ignited flame fronts. The engine is run for 20 hours under cyclic idle and low load conditions to produce heavy deposits conducive toward surface ignition. The surface ignition count is recorded every hour and reported as the average of the surface ignition counts per hours over the period of the test.

SURFACE IGNITION TEST Surface ignition counts/hour Base Fuel 342 Base Fue1+0.05 weight percent of tricaprylmethylammonium borohydride 150 Obviously many modifications and variations of the invention herein set forth may be made without departing from the spirit and scope thereof, and therefore, only such limitations should be imposed as are indicated in the appended claims.

We claim:

1. A motor fuel composition comprising a mixture of hyprocarbons in the gasoline boiling range and containing 0.001 to 0.1 weight percent of a quaternary ammonium borohydride having the formula:

in which R, R, R" and R' are hydrogen or a hydrocarbyl radical having from 1 to 24 carbon atoms and the sum of the carbon atoms in R, R, R and R is at least 18.

2, A composition according to claim 1 in which R, R, R" and R' are aliphatic radicals having from 1 to 12 carbon atoms and the sum of the carbon atoms in R, R, R" and R' is at least 24.

3. A composition according to claim 1 in which said motor fuel has a Reid vapor pressure above about 9.

4. A composition according to claim 1 containing 0.001 to 0.02 weight percent of said quaternary ammonium borohydride.

5. A composition according to claim 1 in which said quaternary ammonium borohydride is tricaprylmethylammonium borohydride.

References Cited UNITED STATES PATENTS 2,756,259 7/1956 Bragdon 260567.6 2,942,935 6/1960 King et al 260567.6 3,102,911 9/1963 Dobratz 4472 3,118,745 1/1964 Knowles et al 44-72 3,227,754 1/1966 Bragdon et a1 260567.6

DANIEL E. WYMAN, Primary Examiner.

Y. H. SMITH, Assistant Examiner.

U.S. DEPARTMENT OF COMMERCE PATENT OFFICE Washington, 0.6. 20231 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,405,014 September 24, 1968 Ronald w. Von Allmen et al.

It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

In the heading to the printed specification, lines 4 and S, strike out "(both c/o Texaco Inc. P. 0. Box 509, Beacon, N. Y. 12508)" and insert instead assignors to Texaco Inc., New York, N. Y. a corporation of Delaware Signed and sealed this 8th day of July 1969.

(SEAL) Attest:

Edward M. Fletcher, Jr.

Attesting Officer Commissioner of Patents WILLIAM E. SCHUYLER, JR. 

1. A MOTOR FUEL COMPOSITION COMPRISING A MIXTURE OF HYPROCARBON IN THE GASOLINE BOILING RANGE AND CONTAINING 0.001 TO 0.1 WEIGHT PERCENT OF A QUATERNARY AMMONIUM BOROHYDRIDE HAVING THE FORMULA: 